SCI. MAR., 61 (Supl. 2): 5-14
SCIENTIA MARINA
1997
ECOLOGY OF MARINE MOLLUSCS. J.D. ROS and A. GUERRA (eds.)
Biology and description of Antisabia juliae sp. nov.,
new Hipponicid gastropod commensal on Turbo spp.
in Laing Island (Papua New Guinea)*
MATHIEU POULICEK1, JEAN-CLAUDE BUSSERS1 and PIERRE VANDEWALLE2
1
Animal Ecology Laboratory and 2Functional Morphology Laboratory, Zoological Institute, Liège University.
22, Quai Van Beneden, B-4020 Liège. Belgium.
SUMMARY: The gastropod family Hipponicidae comprises widely distributed but poorly known sedentary species. On the
beach-rock of the coral reefs of Laing Island (Papua New Guinea) live rich populations of several gastropod Turbo species
of which many specimens have attached to their shell a hipponicid gastropod attributed to a new species, Antisabia juliae.
This new species, described in this paper, appears to have adapted its mode of life on live turbinids in several ways resulting in morphological changes (thin basal plate loosely adherent to the supporting shell, functional eyes, very long snout,
functional radula, small osphradium) and ethological changes (foraging behaviour: it appears to feed on the epiphytic community growing on the host, in the vicinity of the “host” shell). Except for these characteristics, the mode of life appears
quite similar to that of other hipponicid species with few big females surrounded by several much smaller males.
Development occurs within the egg mass inside the female shell and a few young snails escape at the crawling stage.
Key words: Mollusca, Gastropoda, ecology, Hipponicidae, Papua New Guinea, Indopacific.
RESUMEN: BIOLOGÍA Y DESCRIPCIÓN DE ANTISABIA JULIAE SP. NOV., UN NUEVO GASTERÓPODO HIPONÍCIDO COMENSAL DE TURBO
SPP. EN LA ISLA LAING (PAPÚA NUEVA GUINEA). La familia Hiponícidos comprende especies sedentarias ampliamente distribuidas pero poco conocidas. En las costas rocosas de los arrecifes coralinos de la isla Laing (Papúa Nueva Guinea) viven
abundantes poblaciones de varias especies de Turbo, muchos de cuyos ejemplares portan un gasterópodo hiponícido atribuido a una nueva especie, Antisabia juliae, que se describe en este artículo. Esta especie parece haberse adaptado de varias
maneras a vivir sobre los turbínidos vivos, lo que ha conducido a cambios morfológicos (placa basal delgada y ligeramente adherente a la concha de sostén, ojos funcionales, hocico muy largo, rádula funcional, osfradio pequeño) y etológicos
(comportamiento alimentario: parece que se alimenta de la comunidad epifítica que crece sobre el patrón, en la inmediatez
de la concha del “patrón”). Excepto por estas características, el modo de vida parece muy semejante al de otras especies de
hiponícidos, con unas pocas hembras grandes rodeadas de varios machos mucho menores. El desarrollo tiene lugar en el
interior de la masa de huevos, dentro de la concha de la hembra, y unos pocos caracoles juveniles escapan en el estadio de
reptación.
Palabras clave: Moluscos, Gasterópodos, ecología, Hiponícidos, Papua-Nueva Guinea, Indopacífico.
*Received October 1995. Accepted September 1996.
NEW HIPPONICID SPECIES IN PAPUA NEW GUINEA 5
INTRODUCTION
Hipponicidae are a group of widely distributed
but poorly known sedentary gastropods. Except for
a few older papers (i.e., Quoy and Gaimard, 1835)
there is only a small number of articles dealing with
the detailed morphology and life habits of representatives of this family (for a review, see Knudsen,
1991, 1993). Due to the lack of knowledge about
their anatomy, a considerable uncertainty prevails
regarding the delimitation of the Indopacific genera
and species (Knudsen, 1993), particularly in Papua
New Guinea.
Laing Island (4° 10’ 30” S, 144° 52’ 47” E) lies
in the western part of the Bismarck Sea, in the middle of Hansa Bay (Madang Province, northern coast
of Papua New Guinea). This small island is almost
completely surrounded by live coral formations and
has an eroded coral plateau (beach rock), 75 meters
wide, on three sides: east, north and south. On this
plateau live rich populations of Turbo setosus
Gmelin, 1791, T. crassus Wood, 1829, T. brunneus
(Röding, 1798) and T. sparverius Gmelin, 1791, of
which many specimens wear a hipponicid gastropod
attributed to the genus Antisabia that we consider as
a new species. This hipponicid was almost found
only on the shells of these four species.
tilled water at 4°C for 1 hour, washed in distilled
water, dehydrated through graded ethanol series and
dried by sublimation at 10°C under low pressure
after inclusion in Peldri® fluorocarbon resin. The
material was glued onto Al stubs with Tempfix®
conductive resin, Au-Pd sputtered (15 nm) (cold
diode Balzers sputtering device) and examined with
a Jeol JSM-840/A scanning microscope.
DESCRIPTION
Antisabia juliae sp. nov.
Class Gastropoda
Superfamily Hipponicacea Troschel, 1861
Family Hipponicidae Troschel, 1861
Material examined: Over 300 specimens were
observed of which most were returned live to the
beach. Approximately 50 specimens were preserved
for dissection and SEM examination.
MATERIAL AND METHODS
Holotype: A female specimen, collected in May
1995 cemented to a shell of Turbo setosus Gmelin,
1791 on the beach rock at Laing Island (Papua New
Guinea); 4 mm length and 3 mm width; glutaradehyde/OsO4 fixed and ethanol preserved. Deposited
in the collections of the Royal Institute of Natural
Sciences of Belgium in Brussels (IRSNB) under n°
I.G. 28.371A
During three missions on Laing Island in
October-November 1990, 1992 and May-June 1995,
we were able to collect samples for SEM observations and to describe the gross morphology, the spatial and specific distribution of this new Antisabia
species (approx. 300 specimens were observed,
most of which were returned live to the collecting
site according to the wishes of the Papua New
Guinea authorities).
The material was sampled at low tide on the
beach rock. Supporting shells of Turbo spp. were
sized and identified on site and the number, position
on the host and sizes of the hipponicid shells recorded with a caliper square to the nearest 0.1 mm.
Results were computed and interpreted through
Systat® statistical software package.
Some samples were either ethanol preserved for
dissection and radula extraction or glutaraldehyde
fixed for scanning electron microscopy (SEM).
Later, the samples for SEM were washed in 0.2 µm
filtered seawater and postfixed in 0.5 % OsO4 in dis-
Holotype diagnosis: The shell is solid, patelliform in
general shape, with a pyriform aperture. In lateral
view, the anterior edge is convex and the apex is
located quite closer to the posterior margin.
Sculpture is constituted of 6 thick axial undulations
becoming deeper close to the aperture, crossing
irregular growth marks. The shell is whitish pink
under a thin amber periostracum, partly covered by
calcareous algae and other epiphytes. The interior is
glossy white. The protoconch (not well conserved)
is rissoid in shape (Fig. 3B), with 2.5 whorls,
smooth (except superficial granulations due to the
shell fabric) and disposed at right angle of the teleoconch. Its sizes are as follow: 400 µm in length, 270
µm in diameter, nucleus 120 µm in diameter. The
basal plate is partly conserved: it is a thin white calcareous layer on the ventral side of the metapodium,
smaller in diameter than the aperture of the shell.
When observed alive, the head showed a relatively big muscular and very extensible snout (several mm out of the shell; Figs. 1D, 4), the distal ends
6 M. POULICEK et al.
FIG. 1 – Antisabia juliae sp. nov.; A, shell, dorsal view of a female specimen (paratype; scale bar, 250 µm); B, shell, internal view of a female
specimen (paratype; scale bar, 250 µm); C, fingerprint on the surface of a Turbo shell (scale bar, 250 µm); D, anterior cephalic region (scale
bar, 100 µm) c, ctenidium (gill); f, anterior part of the propodium; l, lateral lobe of the snout; o, osphradium; p, mantle edge; t, tentacles.
NEW HIPPONICID SPECIES IN PAPUA NEW GUINEA 7
FIG. 2 – Antisabia juliae sp. nov. A, General view of the radula of a male specimen (scale bar, 50
µm). B, Detail of the anterior part (6 first rows) of the radula of a female specimen (scale bar, 10
µm). C, General view of a young snail recently hatched from the egg capsule. (scale bar, 10 µm).
8 M. POULICEK et al.
of which bear a pair of blunt lateral mobile lobes (l,
Figs. 1D, 4). Tentacles are conical, long and thin
when extended, of the same length or slightly longer
than the snout (t, Figs. 1D, 4), with small brown
ventrolateral eyes at the base. The general colour is
whitish with regular dark brown to black marks on
the distal part of the tentacles (one third of their
length) and on the edges and lateral parts of the
snout except the distal lobes (Fig. 4).
Allotype: A male specimen, collected in May 1995
cemented to the same shell of Turbo setosus Gmelin,
1791 as the holotype, same locality; 2 mm length
and 1.5 mm width; ethanol preserved (IRSNB collections N° I.G. 28.371B).
Allotype diagnosis: The shell (teleoconch) is very
thin, low patelliform in general shape, with an irregular oval aperture. In lateral view, the anterior edge
is convex and the apex is located at the level of the
posterior margin. The shell is almost smooth, with 3
very weak axial undulations. The colour is whitish
pink under a very thin inconspicuous periostracum.
The interior is glossy white with heavy pink very
small blotches close to the aperture of the shell.
The protoconch is rissoid in shape, with 2
whorls, smooth and disposed at right angle of the
teleoconch. Its sizes are as follow: 350 µm in length,
250 µm in diameter, nucleus 120 µm in diameter.
The basal plate is well preserved: reniform in shape,
very thin, composed of juxtaposed spherulithic
granules and only slightly adherent to the host shell.
The colour pattern is similar to that of the holotype.
The penis is prominent, reaching half the length of
the snout, with a blunt shape, disposed on the right
side of the head.
Paratypes: 3 isolated shells, 6 females and 9 males
collected in November 1992 and May 1995, same
locality, deposited in the IRSNB collections under
N° I.G. 28.371C. 4 females and 2 males collected in
May 1995 deposited in the collections of the
Zoology Museum of Liège University (MZULg)
under n° RE13900, RE13901, RE13902, RE13903,
RE13904 and RE13905. 9 females and 13 males
collected in October 1990, November 1992 and May
1995 in the collection of authors.
Etymology: One of the authors, MP, dedicates this
species to his little child Julie, whose birth coincided with the beginning of this work and the first specimens found.
Other morphological features and variations
within the population
The teleoconch is variable in shape and thickness: generally solid, patelliform to conical, it is
more or less elevated according to the size and the
localization of the specimen on the “carrier” mollusk shell (Figs. 1A, B): specimens located on the
external part of the peristomium are generally larger
than specimens on the columellar region of the host
shell (shallower ovoid patelliform shells). The same
observations were made on males and females. The
biggest female specimens observed reach 14 mm in
diameter, the biggest males less than 4 mm.
Sculpture is present in more than 85% of specimens:
it is constituted of 2 to 12 axial undulations becoming deeper closest to the aperture. The colour is generally very pale and uniform, whitish pink to pale
brown in rare specimens under a thin smooth periostracum. The interior is glossy white with occasional
heavy pink to chocolate brown very small blotches
and a thin horse-shoe muscular scar. Concerning the
microarchitecture, the shell is composed of three
superimposed layers of crossed-lamellar fabric with
the general axis of first order blocks of adjacent layers disposed at right angle from each other and second order lamellae displaying a characteristic angle
of 40º to 50°.
The protoconch (when conserved) is naticoid
(Fig. 3a) to rissoid (Fig. 3b) in shape, always with
2.5 whorls, always smooth (except superficial granulations due to the shell fabric, Fig. 2C) and disposed at right angle of the teleoconch (Figs. 2C, 3).
In the population sampled, the size of the protoconch varies as follows: 350-420 µm in length
(rarely up to 600 µm), 250-300 µm (rarely up to 400
µm) in diameter, nucleus 120-150 µm in diameter.
The microstructure of the protoconch is aggregative
spherulithic (Fig. 2C).
FIG. 3 – Camera lucida drawings of the two kinds of protoconch
shapes of Antisabia juliae sp. nov. Scale bar, 300 µm. A, naticoid
shape; B, rissoid shape (female illustrated in fig. 1A).
NEW HIPPONICID SPECIES IN PAPUA NEW GUINEA 9
FIG. 4 – Camera lucida drawing of a ventral view of the head of a
live female adult specimen of Antisabia juliae sp. nov. (paratype).
Note the dark markings on the snout and tentacles. Scale bar, 1000
µm. bp, basal plate; e, eye; f, anterior part of the propodium;
j, jaws; l, lateral lobe of the snout; t, tentacles.
In females, the basal plate (secreted by the ventral surface of the foot), termed “ventral valve” by
Yonge (1953, 1960), is 100 to 250 µm thick and
very loosely cemented to the shell of the host Turbo
(Fig. 1C). It is smaller in diameter than the aperture
of the Antisabia juliae sp. nov. shell so that its free
edges plough a relatively wide and moderately deep
ridge in the support (Fig. 1C). In males, the basal
plate is very thin (30 to 50 µm thick), and only
slightly adherent to the host shell.
The taenioglossate radula is very small (25-40
rows in females, 10-25 in males with no sexual differences in teeth morphology), close to the distal
end of the extended snout (Fig. 2A). The rachidian
tooth (Fig. 5A) is about 25 µm wide with 7 cusps,
the central one being more developed. The lateral
tooth (Fig. 5B) has a large median cusp with 5-6
minor cusps on each side (width of the tooth: 160 180 µm). The curved marginal teeth (Fig. 5C) are
long and thin, with 9-13 distal cusps. The first three
to six rows of the radula are worn away: cusps are
broken or blunt (Fig. 2B).
The digestive tract was not examined in close
details (Fig. 6). There are two small jaws (j, Figs. 4,
6) disposed dorsolaterally. The gut (g, Fig. 6) is
10 M. POULICEK et al.
FIG. 5 – Radular teeth of Antisabia juliae sp. nov. A, rachidian tooth
(Scale bar, 5 µm). B, lateral tooth (Scale bar, 20 µm). C, second
marginal tooth (Scale bar, 20 µm).
FIG. 6 – Schematic drawing of the digestive tract of Antisabia juliae
sp. nov. a, anus; g, gut; i, intestine; j, jaws; ms, horse-shoe muscle
scar; r, radula; sh, shell contour; sn, snout outline; st, stomach.
FIG. 7 – Camera lucida drawing of ventral view of a female
Antisabia juliae sp. nov. with eggs capsule attached to the basal
plate (paratype; scale bar, 1000 µm); bp, basal plate; e, eye; ec, eggs
capsule; f, anterior part of the propodium; me, mantle edge;
sh, shell contour; t, tentacles.
nearly straight. The stomach (st, Fig. 6) is quite wide
and pouched, disposed at the middle to right side of
the posterior body. The digestive gland is greenish
brown, mainly disposed dorsally, to the left part of
the stomach. The intestine is quite long and occupies
a large part of the pallial cavity embedded in the
digestive gland, containing numerous brownishgray to green oval fecal pellets.
The mantle edge is thickened without apparent
differenciations (p, Fig. 1D). The pallial cavity is
quite deep. The osphradium appears as an oval ridge
close to the mantle edge (o, Fig. 1D). The ctenidium
is quite long, transversally disposed, with an L shape
(approx. 50 short filaments; c, Fig. 1D).
In females, egg capsules are attached at the postero-lateral left side of the foot, at the edge of the
basal plate (Fig. 7). Egg capsules (3-24 eggs, 500
µm in diameter) are thin walled pyriform bodies
with a short stalk. Young snails escape at the crawling stage (Fig. 2C). Reproduction (many females
wearing egg capsules) was observed at the beginning of the rainy season (October to November) and,
to a lesser extent, at the end of it (May). Hatching (2
to 10 young snails per capsule) was observed in
November and December.
Comparison with other related species in the
Indopacific region
Antisabia juliae sp. nov. is quite easy to distinguish from other Indopacific species of
Hipponicidae except from coexisting Antisabia conica (Schumacher, 1817) which has quite similar
morphology and life habits: A. juliae has a smaller
size, a much thinner basal plate, weaker sculpture on
the shell and a narrower “preference” regarding the
supporting shell, almost only live turbinids. Egg
capsules of A. conica contain several hundred very
small yellowish eggs, compared to the 3-24 big
whitish eggs in the capsule of A. juliae. Both species
appear evolutively very close.
Other hipponicid species are generally fixed on
rocks, in crevices or on coral heads. Antisabia foliacea (Quoy et Gaimard, 1835) is relatively flat, with
many growth lamellae piled up at the surface of the
shell, each lamella is finely sculptured by radial
threads. Pilosabia subrufa (Lamarck, 1819),
Pilosabia trigona (Gmelin, 1791) and Hipponix
pilosa (Deshayes, 1831) are readily distinguished by
their shaggy or squamose periostracum. Hipponix
antiquatus (Linné, 1767) has a bigger, heavy shell
with axial sculpture composed of very prominent
rugose ribs crossed by microscopic incised lines.
Choice of supporting shell and localization
All specimens of Antisabia juliae sp. nov. of
Laing Island are found on 4 species of Turbinid
gastropods, 3 of which form abundant populations
on the beach rock : Turbo setosus Gmelin, 1791, T.
crassus Wood, 1829, T. brunneus (Röding, 1798). T.
sparverius Gmelin, 1791 is less common. No other
shell was found to harbour any hipponicid species
until 1995 when we found rare specimens on
Trochus maculatus Linnaeus, 1758 (one sample),
Tectus pyramis (Born, 1778) (3 specimens on the
same sample) and Notohaliotis sp. (one sample).
Bigger shells wear a significantly higher number
of commensal individuals than smaller ones (N=60).
There is a direct significant correlation of the number of A. juliae with the size of the host shell (Table
TABLE 1. – Matrix of Spearman correlation coefficients (rs) between number of Antisabia juliae sp. nov. shells and the size and species of the Turbo host shell (number of observations = 60)
Number males
Number females
Species
Size
Number
males
Number
females
Species
0.808*
0.814*
0.223°
1.000
0.938*
0.074°
–
1.000
0.031°
–
–
1.000
* Highly significant (α < 0.01)
° Not significant
NEW HIPPONICID SPECIES IN PAPUA NEW GUINEA 11
FIG. 8 – a, Detail of the epiphytic community scraped off the shell of Turbo setosus (mainly cyanobacteria). Scale bar, 10 µm. b,
Composition of a fecal pellet collected inside the intestine of a female Antisabia juliae nov. sp. living on the Turbo shell illustrated at A:
pennate (benthic) diatoms and cyanobacteria similar to that observed on the shell. Scale bar, 10 µm. c, Detail of the epiphytic community
scraped off the shell of Turbo brunneus (mainly pennate diatoms and filamentous algae). Scale bar, 10 µm. d, Composition of the stomach
content of a female Antisabia juliae sp. nov. living on the Turbo shell illustrated at C: pennate (benthic) diatoms, filamentous algae and
cyanobacteria similar to that observed on the shell. Scale bar, 10 µm.
12 M. POULICEK et al.
1): A. juliae is rare on shells smaller than 20 mm in
length, whereas shells bigger than 60 to 80 mm frequently harbour one or two females (rarely >3) of
relatively large size (6-14 mm diameter) surrounded
by 2 to 6 smaller males (up to 21, 1-3 mm diameter).
The number of males is also strongly correlated to
the number of females (rs= 0.94, α < 0.01).
At the same size, there is no significant difference in the number of specimens of A. juliae on the
3 more abundant species of Turbo (N=57). There is
also no significant correlation between the size of A.
juliae and the size of the host shell.
As already observed by Laws (1971) for
Antisabia conica, most specimens of A. juliae are
found on the ventral columellar region of the shell,
close to the upper part of the peristomium (87 % of
the specimens sampled, N = 250) either on the last
whorl or at the base of the last spiral whorl, 10 % are
found at the external upper part of the peristomium
and 3 % close to the external anterior part of the
shell. Several specimens are generally found close
together with females surrounded by smaller males.
Distribution around Laing Island
Antisabia juliae sp. nov. is quite abundant on
Laing Island, where about 50% of specimens of
Turbo (all species together) harbour one or more
specimens. But its distribution on the beach rock is
not homogeneous: it is much more abundant at the
northern part of the island where more than 80% of
the turbinids wear one or more hipponicid snails.
Along the western side, its occurrence remains fairly high (45% to 60% of turbinid shells) whereas this
species is less represented at the southern sites (5%
to 20% of turbinid shells). There is no important
Turbo population on the eastern (lagoonal) side. On
the beach rock, this distribution is mainly explained
by the mean sizes of Turbo spp.: large specimens (60
to 90 mm high) mainly occur directly on the beach
rock and underneath big dead corals at the northern
and western sides of the island whereas smaller
specimens shelter in crevices of boulders and under
smaller rocks at the southern part of the island.
behave as a filtering snail like Hipponix antiquatus (= H. cranioides) observed by Yonge (1953).
No evidence of host fecal pellet eating was ever
encountered as observed in Hipponix australis
(Risbec, 1935). Living specimens are frequently
seen with the shell not closely affixed to the substrate, the snout and tentacles extruded well away
through the space so produced and browsing on
the host shell. Moreover, the area around A. juliae
shells is generally relatively “clean” compared to
other similar part of the host shell. When compared to the epiphytic community (Figs. 8A, C)
found on the host shell, the composition of stomach content and of fecal pellets (Figs. 8B, D)
shows striking similarities: benthic pennate
diatoms, rhodophyta, chlorophyta and cyanobacteria constitutes the bulk of the pellets with a very
similar composition when compared to the epiphytic community living on the same host shell.
No sand grains were observed as in Hipponix australis analysed by Knudsen (1991).
Any contact stimulus around the snout or tentacles immediately triggers the protrusion of the radula so that this species appears even able to grasp
meiofaunal organisms: a partially digested harpacticoid copepod was even found in two cases. It seems
that A. juliae feeds upon the epiphytic community,
microorganisms and perhaps meiofauna in the area
that can be reached by the snout.
As the basal plate secreted by the foot is only
very loosely cemented to the host shell, we tried to
verify the real sedentary nature of this species even
if no specimen was ever observed moving or even
loose on the host shell. Several attempts (approximately 30 specimens) to let a carefully removed
snail fix itself again on the same or another shell
(with or without the basal plate) never succeeded :
all A. juliae died within 6 to 96 hours except some
small males remaining unattached for more than 6
days. It appears thus probable that this species, like
other in the family Hipponicidae, has real sedentary habits.
DISCUSSION
Foraging
Morphological features (long snout, relative
small size of the gill filaments, structure of the
radula, worn teeth at the anterior edge; Figs. 1D,
2A, 2B) together with observations of live specimens attest that Antisabia juliae sp. nov. does not
The hipponicid Antisabia juliae sp. nov. was
first tentatively attributed to the species Antisabia
conica (Schumacher) but it appears to present several distinct features that let us consider it a new
species. A. juliae sp. nov. appears to have adapted
to its mode of life on live turbinids in several ways
NEW HIPPONICID SPECIES IN PAPUA NEW GUINEA 13
resulting in morphological, ethological and functional changes.
Its preferential location on the basal fasciolar
area of the host shell implies it should be progressively recovered by the growing Turbo shell.
Nevertheless, a displacement reaction of A. juliae
towards “safer” areas is not likely to occur even if
the basal plate secreted by the foot is very thin and
only very loosely cemented to the host shell (compared to the attachment of other Hipponicid species
living on dead shells or on the beach rock, like Sabia
foliacea for example). This can explain the preferential “choice” of large (adult) supporting shells
(with much slower growth) that so limits the risk of
being quickly recovered.
Life on large active intertidal snails also
changes the foraging behaviour of this species
with correlated morphological changes: it appears
to feed on the epiphytic community growing on
the host shell, in the vicinity of the sedentary hipponicid; larger supporting shells are likely to wear
a more diversified and quick growing epibiontic
biocenose with a relatively high turnover.
Associated with this kind of food collecting habit,
this species has developed specific morphological
features: long extensible snout with short mobile
lateral appendages, functional grasping radula,
presence of eyes, etc.
Except for these characteristics, the mode of life
appears quite similar to that of other Hipponicids
with a few large females surrounded by several
much smaller males. Development occurs within the
egg mass inside the female shell and a few young
snails escape at the crawling stage. Indirect observations of the shell structure suggests a quick growth
that should also be considered as an adaptation to
this mode of life.
14 M. POULICEK et al.
ACKNOWLEDGEMENTS
This study was supported by the National Fund
for Scientific Research of Belgium (FNRS) as an
FRFC grant n°29008/90.F. The field work was done
at the King Leopold III Biological Station in Laing
Island (Papua New Guinea). Many thanks are due to
the directors (Prof. J. Bouillon, then Prof. M.
Jangoux), the local manager, technicians and occasional samplers for help and logistic facilities during
our missions. We also want to thank scientific and
administrative authorities of Papua New Guinea in
Port Moresby and Madang for their help and support. The work of Nicole Decloux who prepared the
samples for SEM is greatly acknowledged. Thanks
are due to Professor Charles Jeuniaux and to an
unknown referee for their criticism and constructive
suggestions to improve this paper.
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